Pallet trucks, which are also commonly referred to as pallet jacks, pump lifts, and pump trucks, are wheeled devices used to lift and transport loaded and unloaded pallets on a fork assembly. The construction and operation of pallet trucks is known in the art. Both manual (hand-powered) and powered (motorized) pallet trucks typically employ a lift mechanism employing a linear actuator such as a hydraulic actuator, to raise the fork assembly from a lowered position to provide sufficient clearance between the lower surface of the pallet and the floor to permit travel. Each fork of the fork assembly is supported by load wheels located near the ends of the fork. Travel is controlled by the pallet truck operator, typically by a steering assembly coupled to a drive wheel; thus, the turning radius of the pallet truck is defined at least in part by the wheelbase defined by the distance between the load wheels and the drive wheel. The orientation of the load wheels is typically fixed with respect to the pallet truck; accordingly, the turning radius may be inconveniently large, with the result that the pallet truck can be difficult to maneuver in a crowded or constrained environment.
U.S. Pat. No. 8,336,913, issued to Aaseby et al., describes a steering device for decreasing a turning radius of a manual pallet jack. The steering device comprises a spring-biased wheel mounted to the underside of the jack between an extensible roller and a main wheel. When the pallet jack is in the lowered position such that it is maneuverable to engage a pallet resting on the ground, the spring-biased wheel contacts the ground and provides a shorter turning radius between it and the main wheel of the jack. When the pallet jack is moved to a raised position, however, a larger turning radius is defined by the extensible roller and the main wheel. However, it has been found that the selection of a spring with suitable compressive force can be challenging, as too weak a spring results in the spring-biased wheel losing contact with the ground, while too much spring resistance makes it difficult, but usually impossible, for the wheel to pass over the lower stringer of a pallet. Furthermore, the steering device is only capable of providing the shorter turning radius when the pallet jack is unloaded (and in the lowered position), thus limiting the utility of the steering device.